Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech Review Towards developing a representative biochemical methane potential (BMP) assay for landfilled municipal solid waste – A review Lauretta Feyisetan Pearse a , Joseph Patrick Hettiaratchi a , Sunil Kumar b, ⁎ a Center for Environmental Engineering Research and Education (CEERE), Department of Civil Engineering, Schulich School of Engineering, University of Calgary, Calgary, Alberta, Canada b CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Mrag, Nagpur 440 020, India ARTICLE INFO Keywords: BMP Methane Landfilling Municipal solid waste (MSW) Slurry Field capacity ABSTRACT The applicability of slurry-based (semi-liquids) BMP assay in determining biodegradation kinetic parameters of landfilled waste is critically reviewed. Factors affecting the amount and rate of methane (CH 4 ) production during anaerobic degradation of municipal solid waste (MSW) and optimal values of these factors specific to landfill conditions are presented. The history of conventional BMP, and some existing procedures are reviewed. A landfill BMP (LBMP) assay is proposed that manipulates some of the key factors, such as moisture content, particle and sample size, that affects the rate of CH 4 production and the CH 4 generation potential of landfilled MSW (LMSW). By selecting proper conditions for these factors, a representative BMP assay could be conducted to ensure accurate determinations of CH 4 potential and the kinetic parameters k; first order rate coefficient and L o ; methane generation potential. 1. Introduction The anaerobic degradation process in a landfill accepting biode- gradable organic waste produces landfill gas (LFG), which primarily consists of methane (CH 4 ) and carbon dioxide (CO 2 ). CO 2 and CH 4 are prominent greenhouse gases (GHGs) with CH 4 having a global warming potential 34 times that of CO 2 over the 100-year time period (IPCC 2013), which if left to vent to the atmosphere poses potential climate change impacts. In Canada, about 25% of anthropogenic CH 4 emissions were from landfills in 2001 (Environment Canada, 2002). However, instead of releasing into the atmosphere, CH 4 can be collected and harnessed as a clean renewable source of energy (Bouallagui et al., 2003; Perez Lopez et al., 2005; Forster-Carneiro et al., 2008) or fugitive emissions could be mitigated by oxidizing the CH 4 gas to carbon di- oxide (CO 2 ) through various bio-based technologies such as landfill biocovers, CH 4 biofilters, biowindows or biotarps (Majdinasab and Yuan, 2017). To ensure regulatory compliance, efficient design of gas collection and recovery systems, it is important to accurately quantify the rate and amount of CH 4 generation (Krause et al., 2016). Another reason to accurately quantify CH 4 generation, is in the opportunity to purchase carbon credits as a result of the amount of carbon dioxide equivalent (CO 2 eq) of CH 4 emissions controlled through recovery or mitigation projects. Time dependent CH 4 generation can be predicted using mathematical models, such as the Scholl-Canyon model that follow first order reaction kinetics, in which two primary parameters are used; the CH 4 generation potential L o (m 3 /tonne of waste) and the first-order rate coefficient k (year -1 )(Emcon Associates, 1980; De la Cruz and Barlaz, 2010; Karanjekar et al., 2015; Krause et al., 2016; Majdinasab et al., 2017). These parameters are usually either obtained from published data (USEPA, 2005; IPCC, 2006), or theoretical and experimental means. The theoretical CH 4 potential can be determined from the waste’s chemical oxygen demand (COD) characterization, elemental composition or organic fraction composition (Nielfa et al., 2015). One gram of COD is reported to produce 350 ml CH 4 at standard tempera- ture and pressure (Buffiere et al., 2006). The Buswell formula is used to predict yields from elemental composition, and the Buswell formula is used with organic fraction (i.e., grease, carbohydrate, protein and fiber content) composition (Nielfa et al., 2015; Lesteur et al., 2010). Davidsson et al. (2007) showed that the ultimate CH 4 yield derived from the source-sorted organic fraction of municipal solid waste (SS- OFMSW) gave more comparable value (87%) to that obtained from experimental data than the value derived from elemental composition (74%). A major drawback of theoretical calculations is in the assump- tion that complete mineralization of the waste occurs which is not necessarily a real representation of landfill conditions. Even if the wastes are homogeneous and completely degradable, Wang et al. (2014) stated that 5% of the organic content is used for cell growth https://doi.org/10.1016/j.biortech.2018.01.069 Received 14 November 2017; Received in revised form 10 January 2018; Accepted 15 January 2018 ⁎ Corresponding author. E-mail address: s_kumar@neeri.res.in (S. Kumar). Bioresource Technology xxx (xxxx) xxx–xxx 0960-8524/ Crown Copyright © 2018 Published by Elsevier Ltd. All rights reserved. Please cite this article as: Pearse, .LaurettaF., Bioresource Technology (2018), https://doi.org/10.1016/j.biortech.2018.01.069